Patients who have vasculitis in pregnancy generally have a grim prognosis. Vasculitis occurring during pregnancy may have a more aggressive course and require more aggressive treatment than vasculitis occurring at other times. A 29-year-old woman who presented in the 16th week of her third intrauterine pregnancy was diagnosed as having active microscopic polyangiitis. Therapy consisting of high-dose methylprednisolone and cyclophosphamide was instituted, but the patient died of pulmonary infection due to methicillin-resistant Staphylococcus aureus.